Stretching machine



March 16, 194 M. M. CUNNINGHAM 2,314,318

STRETCHING MACHINE;

Filed Aug. 3, 1940 3 Sheets-Sheet 1 mam. I e F Q E March 16, 1943.

M. M. CUNNINGHAM 2,314,318

STRETCHING MACHINE Filed Aug. 3, 1940 3 Sheets-Sheet 2 he; or:

Patented Mar. 16, 1943 s'rnn'ronmo MACHINE Marion Morgan Cunningham, South Bend, Ind., assignor to Mishawaka Rubber and Woolen Manufacturing Company,

' corporation of vIndiana Application August 3, 1940, Serial No. 350.597

l3 Claims.

This invention relates to stretching machines, and more particularly to power driven machines for stretching fabrics on frames.

It is an object of the present invention to provide a machine which is adapted to simultaneously stretch fabrics or other materials on frames and to secure the materials to the frames.

it is another object to provide a stretching machine which may readily accommodate materials of varying thickness.

it is a further object to provide a machine which will stretch materials with a high degree of uniformity. Y a

It is another object to provide a machine which wlil progressively stretch materials on frames of various shapes.

It is a further object to provide a machine which will stretch and secure together layers of treated or coated fabrics, such as rubberized fabric.

These and other objects not specifically enumerated are contemplated for this invention, as will readily appear to one skilled in the art as the following description proceeds.

In the accompanying drawings:

Figure 1 is a perspective view of a stretching machine embodying the present invention; v

Figure 2 is a fragmentary elevation showing a modification of the invention;

Figure 3 is an enlarged fragmentary front elevation of another modification of the invention;

Figure 4 is a front elevational view;

Figure 5 is an enlarged cross-section taken on the line 5-5 of Figure 4; and

Figure 6 is an enlarged cross-section taken on the line 66 of Figure 4.

Referring to the drawings, a standard 10 has supporting brackets I l and I2 which are provided with journal bearings in which the drive shaft i3 is journaled. Keyed to one end of the shaft i3 is a sprocket it which may be driven through chain l5 by an electric motor or other suitable power means. Also keyed to shaft I3 are gears l6 and I! and at the opposite end, roller IS.

A beam [9 is supported on the standard Ill by bolts 28 and2l. The bolt passes through an elongated vertical slot 22 in standard Ill. The slot may be in either the standard It or beam l9, permitting vertical movement of the end of beam (9 within the limits of the slot. The beam pivots on bolt 2| during such movement. Beam I!) has spaced journal brackets 23 and 24 on which shaft 25 is rotatably mounted. A gear 26 is keyed to the shaft and is in mesh with gear l6. Keyed Mishawaka, Ind., a

to the opposite end is a roller 21 which is in alignment with roller iii.

A shaft 28 is journaled adjacent one end in bracket l I and adjacent the other end in bracket 29, both of which are secured to the standard Iii. A gear 30 is keyed to one end of the shaft and is in mesh with gear H. A smaller gear 3i is keyed to the shaft adjacent gear 38. A worm screw 32 is keyed to the other end of the shaft28.

A shaft 33 is mounted in journal bearings 34 and 35 which are mounted on a bar 36. The bar St is pivotally secured adjacent one end to the bracket II by means of a bolt 31. The bar is supported adjacent the other end by an open bracket 38 which is secured to the standard It. A gear'39 is keyed to one end of theshaft 33, and a worm screw 40 is keyed to the other end opposite screw 32. i

As shown in' broken lines in Figure 6, a counter gear 5! is suitably journaled in the standard I!) and is in mesh with gears 3| and 39. p

As shown in Figure 4, a lever 4| is pivotally secured to the standard It! by a bolt 42 and is connected through a link 43 to the bar 36. Another link Mis secured to the other end of the lever; this link may be secured to a foot pedal or otherwise made available for manipulation by the operator of the machine.

The standard it! is provided with a step 45 through which a threaded rod 46 passes. Mounted on the rod is a coil spring 41 which is seated at its lower end on the journal bracket 24. A pin 48 through the rod prevents upward movement of the spring on the rod. The tension of the spring may be altered by screwing the nuts 49 and 50 up or down on the rod 46.

Further details of construction will be described in connection with the operation of the machine. Referring to Figure 1, layers of fabric 52 and 53 have been placed on either side of a frame member 54. In the present instance, the fabric has been rubberized and the opposing surfaces ad- {here to each other. The materialis placed upon the work table 55 and moved toward rollers l8 and 21. The standard It is provided with a slot 56 to permit the passage of the work beyond it. The periphery of roller 2? has uniformly spaced scoring on it, or it may be knurled to increase 5 the traction of the roller as it contacts the fabric.

Rollers l8 and 21 are'of equal diameter and rotate in opposite directions, roller I8 rotating clockwise and 21 counterclockwise. Roller 21 however runs slower than roller l8,'fcr example, two-thirds as fast, therebycreating a friction point where the fabric is engaged by the rollers.

It will be noted that roller 21 is free to move vertically under the pressure of spring 41 and thereby adapts itself to the thickness of the material inserted. As previously described, the shaft 25 is mounted on the pivotal beam l9 which permits the vertical movement of the roller 21. The tension of spring 41 may be altered to meet various operating conditions.

Worm screws 32 and 40 are driven at equal speeds and are both rotated in a counterclockwise direction, the gears 3! and 39 on the respective shafts being in mesh with the countergear The screws in the present embodiment have a double acme thread; however, a single thread may be used and the speed of the screws increased to accomplish substantially the same result. The shaft 33 to which screw 40 is secured, is rotatably mounted on the pivotal bar 36 so that when link 44 is moved downwardly, the screw 40 is moved upwardly into running meshed position with respect to screw 32. The thread travel of the two screws at the point of contact is in the same direction. The pivotal points and gear clearances in the machine are so arranged as to permit the vertical movement of all screws and rollers. It is apparent that screw 40 could be mounted without permitting such movement, and that screw 32 could be mounted for vertical movement.

It is further contemplated that roller 21 and screw 32 may be mounted for vertical movement, thereby providing a free movable head to allow the accidental passage of thicker objects between the rollers and screws.

As rollers I8 and 21 engage the fabric, the operator raises worm screw 40 into contact with the underside of the fabric and creates a pressure thereon to such an extent that a threading action is produced between screws 32 and 40, causing the fabric to be drawn in the direction of the thread travel.

It will be further noted that rollers I8 and 21 and worm screw 32 revolve in a direction to impart movement to the work, thereby moving it through the machine. Worm screw 40 revolves in a direction counter to the movement of the work, but does not offer enough traction to retard its movement through the machine.

The frame to which the fabric is secured may be of any desired shape, ranging from a square to a true circle, and in order that corners may be turned more easily, the surface speed of the Worm screws is about 50% faster than the surface speed of roller 21. The pivotal point 31 is so arranged that when Worm screw 40 is brought into contact with the fabric in running position by moving link 34 downwardly, the approach of screw 43 to 32 is non-parallel. The resulting graduated pitch-diameter permits the inner periphery of both screws to travel ahead with respect to the fabric as a corner is rounded, and at the same time a stretching force is maintained on the fabric. The work pivots about two centers, one at the contact point between rollers l8 and 27, and the other a line contact between screws 32 and M]; consequently it is desirable to maintain these points in close proximity.

The screws 32 and 40 are positioned ahead of rollers l8 and 21 so that their stretching action pulls the fabrics tightly on the frame and the rollers then roll the fabrics together in a firm bond, maintaining the fabric in taut condition on the frame 54. The rollers also maintain the position of the frame as the fabric is being stretched, since the rollers contact the material between the frame and the screws preventing it from 'being drawn in the direction the screws are stretching the material.

Figure 3 shows a modified type of roller. These rollers are provided with a peripheral groove 51 which is-substantially the width of the frame member 54 shown in cross-section between the rollers 58 and 59. The depth of each groove corresponds approximately to one half of the thickness of the frame member. These rollers operate in the same manner as rollers I8 and 21 shown in Figure 4, but roll the fabric together on both sides of the frame.

The rollers 6B and BI, shown in Figure 2, have different diameters; consequently the shafts on which they are mounted may be rotated at the same speed. The surface speed of roller 60 will be less than that of roller Bl, which will produce a frictional rubbing action on the fabric as described in connection with rollers l8 and 21, which are of the same diameter but are rotated at different speeds.

It is to be understood that the invention is not limited to the exact embodiment of the device shown, which is merely by way of illustration, as

. various and other forms of the device will be apparent of course to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

I claim:

1. A stretching device comprising a standard, rollers for engaging a piece of work, a shaft pivotally connected to said standard and having one of said rollers mounted thereon, means for 1'0- t'ating said rollers, worm screws for engaging said work and stretching same against the constraint of said rollers, a second shaft pivoted to said standard and having one of said screws mounted thereon, means for rotating said screws, and means for pivoting said shaft to move one of said screws into threaded relation with respect to another of said screws.

2. A stretching device comprising a standard, rollers for fric'tionaliy engaging a piece of work mounted on said standard, one of said rollers being yieldaoly mounted with respect to said standard, means for rotating said rollers with unequal surface speeds to enhance said frictional engagement, worm screws for engaging said work and stretching the same against the restraint of-said rollers, said screws being mounted on said standard, means for rotating said screws in the same direction, and means for moving one of said screws into threaded relation with resp to another of said screws.

2. A stretching device comprising a pair of rollers for engaging opposite surfaces of a piece of work, means for rotating said rollers in op- P directions at unequal surface speeds for I said work and restraining the same lateral movement, a pair of worm screws for engaging opposite surfaces of said work and stretching the same against the restraint of said rollers, means for rotating said screws in the same direction, and means for moving one of said screws into threaded relation with respect to the other screw.

t. A stretching device comprising rollers for engaging opposite surfaces of a piece of work, means for rotating said rollers with unequal sur face speeds for advancing said work and restraining the same against lateral movement, worm screws adjacent said rollers for engaging opposite surfaces of said work and stretching the same against the restraint of said rollers, and

means for rotating said screws with a surface speed greater than that of said rollers.

5. A stretching device comprising a pair of rollers for engaging opposite surfaces of a piece of work and restraining the same against lateral movement, one of said rollers being yieldably mounted with respect to the other, a pair of worm screws for engaging opposite surfaces of said work and stretching the same against the restraint of said rollers, means for moving one of said screws into and out of threaded relation with respect to the other screw, and means for rotating said rollers and screws.

6. A device for stretching material on a frame comprising rollers having peripheral grooves for engaging opposite surfaces of said material at points on both sides of said frame and restraining the same against lateral movement, worm screws adjacent said rollers for engaging opposite surfaces of said material and stretching the same against the restraint of said rollers, and means for rotating said rollers and screws.

7. A stretching device comprising a pair of rollers for engaging opposite surfaces of a piece of work and restraining the same against lateral movement, one of said rollers having a greater diameter than the other, means for rotating said rollers at the same speed whereby the peripheral speed of the roller of greater diameter is higher than that of the roller of lesser diameter, worm screws adjacent said rollers for engaging opposite surfaces of said work and stretching the same against the restraint of said said rollers, and means for rotating said screws.

8. A stretching device comprising a standard, a shaft pivotally mounted on said standard, a work engaging roller on said shaft, a second shaft pivotally mounted on said standard, a work engaging wcrm screw on said second shaft, a second roller and screw for engaging said work opposite said first named roller and screw respectively, resilient means for maintaining said rollers in running engagement with said work and frictionally restraining the same against lateral movement, means for moving said first named screw into threaded relation with said second named screw, and means for rotating said rollers and screws whereby said work is advanced by said rollers and stretched by said screws against the restraint of said rollers.

9. A device for stretching material on a frame comprising worm screws for engaging opposite surfaces of the material, means disposed between said screws and the frame for restraining said frame against lateral movement and for progressively moving the material and frame through said device.

10. A stretching device comprising a pair of oppositely disposed work engaging rollers for advancing the work and restraining the same against lateral movement, a pair of oppositely disposed work engaging worm screws adjacent said rollers for stretching the work against the restraint of said rollers, means for moving one of said rollers and one of said screws toward and away from the other roller and screw respectively, means for rotating said rollers in opposite directions with unequal surface speeds, and means for rotating said screws in the same direction with surface speeds greater than that of said rollers,

11. A device for stretching material on a frame comprising worm screws for engaging opposite sides of said material and stretching the same laterally, rollers for engaging opposite sides of the material at a point between said screws and said frame for advancing the material and frame and restraining the same against lateral movement, and means for rotating said rollers and screws.

12. A device for stretching material superimposed on either side of a frame comprising worm screws for engaging the outer surfaces of said material and stretching the same laterally,

rollers adjacent said screws for engaging the outer surfaces of said material adjacent said frame and restraining said material and frame against lateral movement, and means for rotating said screws and rollers.

13. A stretching device comprising a pair of oppositely disposed work engaging rollers for advancing the work and restraining the same against lateral movement, a pair of oppositely disposed work engaging worm screws adjacent said rollers and positioned in advance of said rollers for stretching the material against the restraint of said rollers, the surfaces of said rollers being in substantial alignment with the surfaces of said screws at the point of engagement with said work, means for rotating said rollers at unequal surface speeds, and means for rotating said screws at a surface speed greater than that of said rollers.

MARION MORGAN CUNNINGHAM. 

